In superficial mycosis, fungi invade mainly into the epidermal stratum corneum, and grow therein. Thus, in order to exhibit excellent pharmacological activities in the treatment of superficial mycosis, antifungal agents should stay in a high concentration in the infected epidermal stratum corneum for a prolonged time, in addition to their potent antifungal activity.
Recently, in order to achieve the above purpose, there have been developed and practically used antifungal agents having a high affinity for keratin, which exhibit clinical effects thereof in the treatment of superficial mycosis only by a single application per day. However, in order to obtain a sufficient affinity for the epidermal stratum corneum, antifungal agents should be formulated so that they can penetrate into the epidermal stratum corneum. However, these antifungal agents having a high affinity for keratin are not readily soluble, and it is difficult to increase their solubility when incorporated in the base. As a result, the penetration into the epidermal stratum corneum of these agents is not sufficient so as to form an antifungal composition for external use which is retentive in the stratum corneum using a high affinity for keratin of the active antifungal agent per se at the maximum.